US Navy Virginia Class Nuclear Attack Submarines

Brumby

Major
Yes i have see this data for Seawolf and the Ocean.
Nevertheless, the underwater detection is a very confidential matter/secret almost like nuclear deterrence then impossible get exact data, in general comparison between submarines.
And also depends conditions temperature, salinity for the propagation of noise or waves sonar.
Seawolf and Virginia sems extremely close, the best with Astute maybe Seawolt a little little more quiet ? A question for Jeff ;)

The intention was not to get exact data and as you mentioned that there are other variables in play. I think the decibels or relative quiteness helps (even though it is not official) to get a sense of relativism. If someone tells me it is more quiet vs. it is 10 times more quiet it does provide some perspective and personally for me it is meaningful.
 

SamuraiBlue

Captain
I would like to make a qualification to my earlier post regarding the type 093 acoustic reading at 110 decibel. The source of that information came from an article which itself reference to a report "Chinese Evaluations of the U.S. Navy Submarine Force and China’s Future Nuclear Submarine Force". That report (which is truncated) that I have looked at does not actually mentioned the type 093 decibel reading. So the reading has to be read with suspicion but for consistency with the other readings in that article I have adopted it.

In contrast, the work by Tom Stefanick’s Strategic Antisubmarine Warfare and Naval Strategy, reported a reading of 130-150 decibels for the type 093/094. The difference between the two sources are very wide and the significance needs to be understood in the context of development against say the Los Angeles. The former places the Chinese submarine development growth as a major leap as oppose to the latter which still places it behind the original Los Angeles. Personally I think the latter is probably the case because the type 093 is a second generation development. I would suspect the type 095 is probably closer to that former reading when it is launched rather than the type 093. Sorry for this long winded non related spill which after all is a Virginia thread.

Although in Japanese, here is an interesting chart of decibel and how it equates in normal life sound.
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At 120 dB it is same as standing next to a roaring jet engine.
110dB a honk on the horn of a car 2m in front of you
100dB under a bridge as a train crosses over
90dB Inside a loud factory, a dog barking in front of you 5 m away, inside a karaoke box with people singing
80dB Inside riding a subway, Listening to a piano playing Beyer 104
etc.

I recently found it is not just the level of sound that you listen into but also the frequency that is tuned in. Like astronomy there is a certain frequency you listen into that is isolated from natural disturbance or in the case detecting subs, frequencies frequently used by man that is mostly artificial which is harmonics of 60Hz since most all electronics are set at this frequency.
 

FORBIN

Lieutenant General
Registered Member
Others data and infos on this excellent blog
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particularly
Ocean background noise - 90 decibels
Seawolf-class - 95 decibels
Virginia-class - 95 decibels
636 Kilo class - 105 decibels
Akula-class - 110 decibels
Improved Los Angeles -105 - 110 decibels
Type 093 - 110 decibels
Type 094 - 120 décibels
Prior to the late 1970s, Soviet nuclear submarines were on average 20 dB to 40 dB louder than their American counterparts
Once the Soviet's became aware of their vulnerability, the Soviet Navy mounted an aggressive quieting effort resulting in a 30 dB drop in radiated noise of Soviet submarines from 1975 to 1988

Minimum noise to slow speed max 10/20 kn, with this DB number seems last SSN very close of Ocean background noise difficult udapte quietness but again possible for more fast speed.
 

Bernard

Junior Member
Navy Looking at Accelerating VPM Design to Allow Earlier Production
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Virginia-class attack submarine Minnesota (SSN-783) under construction in 2012. US Navy Photo

WASHINGTON, D.C. — The Navy is looking into the feasibility of accelerating design and development work on the Virginia Payload Module (VPM) in case the service decides to begin production earlier than the 2019 planned start, Navy acquisition chief Sean Stackley said Wednesday at a House Armed Services Committee (HASC) hearing.

The VPM will add 28 missile tubes to Block V Virginia-class attack submarines (SSN-774), to provide more strike capability from undersea as the fleet prepares to lose the Ohio-class SSGN guided missile submarine fleet in the mid-2020s. The Navy planned to start VPM construction in conjunction with the next Virginia-class multiyear contract in 2019, but Stackley said that the SSGNs represent a 600-missile capacity and that sooner is better when it comes to rebuilding that strike capacity.

Stackley told the HASC seapower and projection forces subcommittee that he had spoken to the Program Executive Office for Submarines and to the submarine industrial base “to take a look at, can we in fact complete those design and development activities earlier than the 2019 timeframe to give the Navy and the nation the option to determine whether or not we want to advance Virginia Payload Modules earlier than the submarine build cycle.”

“We’re looking at first, can we pull [design and development] to the left a year, and the other aspect is what would be our ability to increase the rate of production of VPMs beyond one per year, which is in our current long-range plan.,” Stackley later elaborated. “Affordability comes into play, industrial base capacity comes into play.”

He said the discussions were ongoing and he would know by March or April what the options were in terms of accelerating VPM progress, though subcommittee chairman Rep. Randy Forbes (R-Va.) pressed for the information sooner to help inform ongoing budget discussions in Congress.

The
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that it would add a 70-foot section to the new-construction Virginia-class subs, and that section would include four Virginia Payload Tubes. Each tube would contain seven Tomahawk Land Attack Missiles (TLAM), bringing the submarine’s total load from 12 to 40 TLAMs. The VPM addition would be made beginning with the Block V version of the subs, which would be bought in the 2019 multiyear contract.

One problem the Navy and industry will face, however, is a sharp spike in workload by the end of the decade. Virginia-class submarine procurement is set at two-a-year, but General Dynamics Electric Boat and Newport News Shipbuilding are not currently delivering the subs that quickly. Even as the yards are ramping up to achieve two-a-year delivery, they will need to prepare for one-a-year – or more – VPM production in 2019 and Ohio-replacement ballistic missile submarine production in 2021, according to current Navy plans.

Stackley told reporters after the hearing that the Ohio-replacement was the top priority and needed to stay on schedule regardless of what happens. An ongoing Submarine Build Strategy is looking at what options the Navy and industry have to prepare for the steep uptick in work as the new programs head toward construction.

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Does this mean block V will start earlier?
 

FORBIN

Lieutenant General
Registered Member
Navy Looking at Accelerating VPM Design to Allow Earlier Production
John Warner commissioned this year and homeported to Norfolk, the first Virginia no homeported to Groton or Pearl Harbor.
 

Jeff Head

General
Registered Member
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Does this mean block V will start earlier?
Excellent article...and excellent find Bernard!

I think this is a good idea if they can swing it.

As to whether it means starting Block V a year earlier...or simply adding the VPM to the last of the Block IV boats...I do not know.

I do know this. I expect that the first vessel with the VPM addition is going to take longer to build, and then longer to outfit and test and commission than the other boats. So...the sooner they can start, the better.

Part of the reason for pulling it in earlier may be to account for this.
 

strehl

Junior Member
Registered Member
John Warner commissioned this year and homeported to Norfolk, the first Virginia no homeported to Groton or Pearl Harbor.

Will I ever live long enough to see some politician show any class and decline having his name plastered over a [place aircraft carrier/sub/base you name it] that used to have meaningful names. Do they really think they deserve this? It doesn't matter if the Navy is resorting to cynical ploys to gain political support. They could simply say the truth that they are not worthy of it.
 
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